A technique is known from NON-Patent document no. 1, for example, in which portions of a human body are recognized based on a distance image (depth image) of the human body to localize joint positions of the human body.
However, according to the prior art as described above, it is difficult to increase accuracy of the calculated joint positions, because the joint portions in the distance image are smaller in size than non-joint portions. It is difficult to calculate a joint angle with high accuracy based on the joint positions calculated with decreased accuracy.
[Non-Patent Document 1] “Real-time human pose recognition in parts from a single depth images” by J. Shotton, A. Fitzgibbon, M. Cook, T. Sharp, M. Finocchio, R. Moore, A. Kipman, and A. Blake, In Proc. CVPR, 2011”.
[Patent Document 1] International Publication Pamphlet No. WO2012/077286
[Patent Document 2] Japanese Laid-open Patent Publication No. 2014-68714
[Patent Document 3] Japanese Laid-open Patent Publication No. 2014-136137